Mount apparatus to be mounted on main body of image forming apparatus, and image forming apparatus including mount apparatus

ABSTRACT

A mount apparatus to be mounted on a top surface, in a vertical direction, of a main body of an image forming apparatus configured to form an image on a sheet, includes a latch member extending toward the main body from a surface facing the top surface of the main body and being rotatable around a rotational axis extending in a direction along a direction orthogonal to the vertical direction, and a biasing member configured to bias the latch member in a predetermined rotation direction. The latch member is inserted into the main body through an opening that is provided on the top surface of the main body and is engaged with the main body by a biasing force of the biasing member in a state where the mount apparatus is mounted on the main body.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a mount apparatus to be mounted on atop surface, in a vertical direction, of a main body of an image formingapparatus that forms an image on a sheet, and to an image formingapparatus including the mount apparatus.

Description of the Related Art

An image forming apparatus, on a top surface of a main body of which ina vertical direction an optional apparatus is mountable, is well known.Examples of the optional apparatus include a sheet stacking apparatusand a sheet post-processing apparatus that performs post-processing suchas binding processing. For example, in an apparatus discussed inJapanese Patent Application Laid-Open No. 2003-76090, a positioningmember is provided on a bottom surface of the sheet post-processingapparatus, and the positioning member is inserted into a hole of the amain body of the image forming apparatus so that the sheetpost-processing apparatus is positioned with respect to the main body.

In the apparatus configuration discussed in Japanese Patent ApplicationLaid-Open No. 2003-76090, a fitting length of the positioning memberprovided in the sheet post-processing apparatus with the positioningmember receiving hole provided in the main body is made sufficientlylarge, which stabilizes a posture of the sheet post-processing apparatuseven if an external force is applied to the sheet post-processingapparatus. Along with downsizing of the image forming apparatus,however, the space for a sufficiently large fitting length may not besecured in some cases, unlike the apparatus discussed in Japanese PatentApplication Laid-Open No. 2003-76090. As a result, there is an issuethat the sheet post-processing apparatus is easily inclined with respectto the image forming apparatus in a case where the external force isapplied to the sheet post-processing apparatus.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a mount apparatus to bemounted on a top surface, in a vertical direction, of a main body of animage forming apparatus configured to form an image on a sheet, includesa latch member and a biasing member. The latch member extends toward themain body from a surface facing the top surface of the main body, isrotatable around a rotational axis extending in a direction along adirection orthogonal to the vertical direction, and includes a firstprotrusion and a second protrusion. The first protrusion protrudes in adirection intersecting the direction in which the latch member extends,and the second protrusion is provided on a distal end side of the latchmember relative to the first protrusion and protrudes in a directionopposite to the direction in which the first protrusion protrudes. Thebiasing member is configured to bias the latch member in a predeterminedrotation direction. The first protrusion is inserted into the main bodythrough an opening provided on the top surface of the main body and isengaged with the main body by a biasing force of the biasing member in astate where the mount apparatus is mounted on the main body. In a casewhere the mount apparatus is inclined with respect to the main body in adirection in which engagement of the first protrusion with the main bodyis released, the second protrusion is engaged with the main body so asto regulate inclination of the mount apparatus.

According to another aspect of the present invention, an image formingapparatus includes a main body of an image forming apparatus configuredto form an image on a sheet, and a mount apparatus mounted on a topsurface of the main body in a vertical direction. The mount apparatusincludes a latch member and a biasing member. The latch member extendstoward the main body from a surface facing the top surface of the mainbody. The latch member is rotatable around a rotational axis extendingin a direction along a direction orthogonal to the vertical direction.The latch member includes a first protrusion and a second protrusion.The first protrusion protrudes in a direction intersecting the directionin which the latch member extends, and the second protrusion is providedon a distal end side of the latch member relative to the firstprotrusion and protrudes in a direction opposite to the direction inwhich the first protrusion protrudes. The biasing member biases thelatch member in a predetermined rotation direction. The first protrusionis inserted into the main body through an opening provided on the topsurface of the main body and is engaged with the main body by a biasingforce of the biasing member in a state where the mount apparatus ismounted on the main body. In a direction in which engagement of thefirst protrusion with the main body is released, the second protrusionis engaged with the main body so as to regulate inclination of the mountapparatus.

According to yet another aspect of the present invention, a mountapparatus to be mounted on a top surface, in a vertical direction, of amain body of an image forming apparatus configured to form an image on asheet, includes a latch member that extends toward the main body from asurface facing the top surface of the main body and is rotatable arounda rotational axis extending in a direction orthogonal to the verticaldirection, and a biasing member configured to bias the latch member in apredetermined rotation direction. The latch member is inserted into themain body through an opening that is provided on the top surface of themain body and is engaged with the main body by a biasing force of thebiasing member in a state where the mount apparatus is mounted on themain body.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an image forming apparatusand a sheet post-processing apparatus.

FIGS. 2A and 2B are a perspective view of the image forming apparatusand a perspective view of the sheet post-processing apparatus accordingto a first exemplary embodiment.

FIGS. 3A and 3B are explanatory diagrams of an operation of a latchmember according to the first exemplary embodiment.

FIGS. 4A to 4E are explanatory diagrams of the operation of the latchmember according to the first exemplary embodiment.

FIGS. 5A and 5B are state diagrams when an external force is appliedfrom a stacking unit to the sheet post-processing apparatus.

FIGS. 6A to 6D are explanatory diagrams of an operation of a latchmember according to a second exemplary embodiment.

FIG. 7 is an explanatory diagram of a latch member according to a thirdexemplary embodiment.

FIGS. 8A to 8D are explanatory diagrams of an operation of the latchmember according to the third exemplary embodiment.

DESCRIPTION OF THE EMBODIMENTS

Some preferred embodiments of the present invention are described withreference to drawings. FIG. 1 is a schematic cross-sectional view of aprinter that is an example of an image forming apparatus to which theexemplary embodiment of the present invention is applied. FIG. 1illustrates a main body of an image forming apparatus 100 (hereinafter,referred to as apparatus main body). A sheet post-processing apparatus(sheet stacking apparatus) 200 serving as an optional apparatus (mountapparatus) is mounted on a top surface of the apparatus main body 100 ina vertical direction. FIG. 2A is a perspective view of the sheetpost-processing apparatus 200, and FIG. 2B is a perspective view of theapparatus main body 100.

The apparatus main body 100 includes an image forming unit 101. A sheetfeeding unit 102 feeds a sheet to the image forming unit 101, and afixing unit 103 fixes an image on the sheet.

The image forming unit 101 includes a photosensitive drum 111, anexposure device 113, a charging roller 112, a development device 114,and a transferring roller 115. The photosensitive drum 111 rotates in aclockwise direction in FIG. 1. The charging roller 112, the transferringroller 115, and the development device 114 are disposed substantially inthis order along the rotation direction of the photosensitive drum 111.The image forming unit 101 forms a toner image on a sheet S throughimage forming processing.

The sheet feeding unit 102 includes a sheet feeding cassette 105, asheet feeding roller 106, a conveyance guide 109, and a registrationroller 110. In the sheet feeding cassette 105, a plurality of sheets onwhich an image is to be formed is stacked. The fixing unit 103 includesa fixing roller 116, a pressurizing roller 117, and a conveying roller118. The pressurizing roller 117 is in contact with the fixing roller116. A first sheet conveyance path 122 guides and conveys the sheet thathas passed through the conveying roller 118.

A first switching member 119 and a second switching member 120 areprovided on the first sheet conveyance path 122. A sheet dischargeroller 123 discharges and stacks the sheet to a first stacking unit 124.A full-stacking detection lever 125 detects full stacking of sheetsstacked on the first stacking unit 124. A second sheet conveyance path127 is branched from the first sheet conveyance path 122, and guides asheet to the sheet post-processing apparatus 200. A third sheetconveyance path 128 guides a sheet in double-sided printing. The thirdsheet conveyance path 128 includes a branching portion 129, and areversing roller 121 is provided on the downstream of the branchingportion 129.

The first switching member 119 is switched between conveying the sheetto the downstream of the first sheet conveyance path 122 and guiding thesheet to the third sheet conveyance path 128. The second switchingmember 120 is switched between guiding the sheet to the second sheetconveyance path 127 and guiding the sheet to the stacking unit 124.

After the sheet is guided by the third sheet conveyance path 128 and atrailing end of the sheet passes through the branching portion 129, therotation direction of the reversing roller 121 is reversed to guide thesheet to a sheet re-feeding conveyance path 126. The sheet re-feedingconveyance path 126 is joined to the conveyance guide 109 on theupstream of the registration roller 110, and the sheet is conveyed tothe image forming unit 101 again.

A configuration of the sheet post-processing apparatus 200 that ismounted on the top surface of the apparatus main body 100 in thevertical direction is to be described. The sheet post-processingapparatus 200 includes a fourth sheet conveyance path 201 and a sheetconveyance unit 2010. The fourth sheet conveyance path 201 receives thesheet that has been guided and conveyed by the second sheet conveyancepath 127 in the apparatus main body 100. The fourth sheet conveyancepath 201 includes branching portions at which three conveyance paths arebranched from the fourth sheet conveyance path 201. The three conveyancepaths include discharging units 2140, 2150, and 2160, respectively, todischarge the sheet to the outside of the sheet post-processingapparatus 200. Switching members 214, 215, and 216 to switch theconveyance direction of the sheet are provided at the respectivebranching portions. The sheet post-processing apparatus 200 furtherincludes sheet stacking units 210, 211, and 212 on which the sheetsdischarged by the discharging units 2140, 2150, and 2160, respectively,are stacked. The sheet stacking units (plurality of stacking units) 210to 212 are trays provided on one of surfaces of a sheet post-processingapparatus 200. The sheet post-processing apparatus 200 includes sheetconveyance units 2010 and 2011, the fourth sheet conveyance path 201,and the discharging units 2140 to 2160. A sheet post-processing unit 202and the sheet conveyance unit 2011 that conveys the sheet toward thesheet post-processing unit 202 are provided on the downstream of thethree branching portions of the fourth sheet conveyance path 201 in thesheet conveyance direction. A stacking unit 208, with a sheet on whichthe post-processing has been performed by the sheet post-processing unit202 being stacked thereon, is provided on the downstream of the sheetpost-processing unit 202 in the sheet conveyance direction.

The sheet post-processing unit 202 includes an intermediate stackingunit 203, a first alignment section 204, paired conveying rollers 205, asecond alignment section 206, and a post-processing section 207. Thefirst alignment section 204 aligns the sheet in the conveyancedirection. The paired conveying rollers 205 are contactable to andseparable from the sheet. The second alignment section 206 aligns thesheet in a width direction.

A fifth sheet conveyance path 209 guides and receives the sheet that hasbeen guided and conveyed by the third sheet conveyance path 128 in theapparatus main body 100. Next, an operation of the apparatus main body100 and the sheet post-processing apparatus 200 is described.

A case where a sheet is discharged to and stacked on the first stackingunit 124 is to be described. A sheet on which the image has been fixedby the fixing unit 103 is conveyed by the conveying roller 118 to thedownstream. The first switching member 119 is switched to a rightposition out of two positions illustrated in FIG. 1 and held by anactuator (not shown). Further, the second switching member 120 isswitched to an upper position out of two positions illustrated in FIG. 1and held by the actuator (not shown). The sheet is discharged by thesheet discharge roller 123 and stacked on the first stacking unit 124.When a predetermined number of sheets or more is stacked on the firststacking unit 124 and the full stacking of the sheets is detected by thefull-stacking detection lever 125, a control unit (not shown) performscontrol so as not to convey the sheet to the first stacking unit 124until the sheets on the first stacking unit 124 are removed.

A case where the sheet is discharged to and stacked on the secondstacking unit 208 is to be described. The first switching member 119 isheld at the right position out of the two positions illustrated in FIG.1, and the second switching member 120 is held at a lower position outof the two positions illustrated in FIG. 1. The sheet conveyed by theconveying roller 118 to the downstream is conveyed to the sheetpost-processing unit 202 through the second sheet conveyance path 127and the fourth sheet conveyance path 201. In a case where thepost-processing is not performed on the sheet, the paired conveyingrollers 205 are located at a contacted position, and the sheet isdischarged to and stacked on the second stacking unit 208. When apredetermined number of sheets or more is stacked on the second stackingunit 208 and the full stacking of the sheets is detected by afull-stacking detection lever 213, a control unit (not shown) performscontrol so as not to convey the sheet to the second stacking unit 208until the sheets on the second stacking unit 208 are removed. In a casewhere the post-processing is performed on the sheet by thepost-processing section 207, the paired conveying rollers 205 areseparated from each other, and the sheet is stacked on the intermediatestacking unit 203. Thereafter, the second alignment section 206 alignsthe sheet in the width direction, and further, the first alignmentsection 204 comes into contact with an upper surface of the stackedsheet, thereby aligning the sheet in the conveyance direction. When thealignment processing is performed on each page and the alignmentprocessing on a predetermined number of sheets is completed, thepost-processing section 207 performs binding processing on a bundle ofthe sheets. After the binding processing is completed, the pairedconveying rollers 205 that have been separated from each other are movedto the contacted position and rotated, which causes the sheet bundle tobe discharged to and stacked on the second stacking unit 208 from theintermediate stacking unit 203. In a case where the sheet is dischargedto and stacked on any of the stacking units 210, 211, and 212, theswitching members 214, 215, and 216 are switched by the actuator (nowshown), and the sheet is accordingly conveyed to a desired stackingunit.

An operation in a case where printing is performed on both surfaces ofthe sheet is to be described. The first switching member 119 is held ata left position out of the two positions illustrated in FIG. 1, and thesheet is guided to the fifth sheet conveyance path 209 in the sheetpost-processing apparatus 200 through the reversing roller 121 and thethird sheet conveyance path 128. When the trailing end of the sheetpasses through the branching portion 129, the rotation direction of thereversing roller 121 is reversed, and the sheet is guided to the sheetre-feeding conveyance path 126. Thereafter, the sheet passes through theimage forming unit 101 and the fixing unit 103, thereby double-sidedprinting is performed on the sheet. Thereafter, the switching membersare switched so that the sheet is discharged to a desired stacking unit.

A latch member provided in the sheet post-processing apparatus 200 thatis a feature of the first exemplary embodiment is to be described.

FIG. 2A is a perspective view of the sheet post-processing apparatus 200as viewed from a bottom surface side. FIG. 2B is a perspective view ofthe apparatus main body 100 as viewed from a top surface side.Positioning members 220 and 221, latch members 222 and 223, and a firstconnector 224 are provided on the bottom surface of the sheetpost-processing apparatus 200 in the vertical direction. On the otherhand, positioning member receiving holes (positioning) 225 and 226,latch member receiving portions 227 and 228, and a second connector 229are provided on the top surface of the apparatus main body 100 in thevertical direction.

The latch members 222 and 223 and the positioning members 220 and 221extend toward the apparatus main body 100 from the bottom surface of thesheet post-processing apparatus 200 in the vertical direction that facesthe top surface of the apparatus main body 100 in the verticaldirection.

The positioning member 220 is inserted into the positioning memberreceiving hole 225, and the positioning member 221 is inserted into thepositioning member receiving hole 226. Root portions of the positioningmembers 220 and 221 are fitted in the positioning member receiving holes225 and 226, respectively. As a result, the sheet post-processingapparatus 200 is positioned relative to the apparatus main body 100 infront-rear and right-left directions. Further, the latch member 222 isengaged with the latch member receiving portion 227, and the latchmember 223 is engaged with the latch member receiving portion 228.Details of the configurations and operations of the latch members andthe latch member receiving portions are described below.

When the first connector 224 is connected to the second connector 229,power is supplied to the sheet post-processing apparatus 200 through theconnectors, and communication between the control unit (not shown) ofthe sheet post-processing apparatus 200 and the control unit (not shown)of the apparatus main body 100 is performed through the connectors.

FIGS. 3A and 3B are diagrams of a latch unit 230 that includes the latchmember 222 (also 223) as viewed from the direction same as the directionin FIG. 1. The latch unit 230 includes a base plate 231, a rotary shaft232, and an elastic member (compression spring) 233 serving as a biasingmember. The rotary shaft 232 is fixed to the base plate 231, and thelatch member 222 is rotatable around the rotary shaft 232 that extendsin a direction orthogonal to the vertical direction. The latch member222 is biased by the elastic member 233 so as to be rotated in acounterclockwise direction in FIGS. 3A and 3B, and the latch member 222is brought into contact with a mechanical stopper 234 provided on thebase plate 231 so that a posture of the latch member 222 is determined.FIG. 3A is a diagram illustrating a state where the latch member 222 ispositioned at a home position. FIG. 3B is a diagram illustrating a statewhere the latch member 222 is rotated by receiving an external force forrotating the latch member 222 in the clockwise direction. The latchmember 222 includes a first protrusion 235 and a second protrusion 236.The base plate 231 is fixed to a housing of the sheet post-processingapparatus 200. The first protrusion 235 protrudes in a directionintersecting the direction in which the latch member 222 extends. Thesecond protrusion 236 is provided on a distal end side of the latchmember 222 relative to the first protrusion 235 and protrudes in adirection opposite to the direction in which the first protrusion 235protrudes.

FIGS. 4A to 4E are diagrams illustrating a configuration and anoperation of the latch member 222 and peripheral members thereof whenthe sheet post-processing apparatus 200 is moved downward in thesubstantially vertical direction and is mounted on the apparatus mainbody 100. The latch member receiving portion 227 (228) as an openingincludes exterior covers 240 and 241, a first receiving portion 242, anda second receiving portion 243. FIG. 4A illustrates a state before thelatch member 222 and the latch member receiving portion 227 come intocontact with each other. FIG. 4B illustrates a state where the sheetpost-processing apparatus 200 is slightly moved in the vertical downwarddirection from the position illustrated in FIG. 4A, and the firstprotrusion 235 and the exterior cover 241 are in contact with eachother. At this time, there is a gap between the second protrusion 236and both of the exterior cover 240 and the second receiving portion 243.Before the state illustrated in FIG. 4B, the positioning members 220 and221 are fitted in the positioning member receiving holes 225 and 226,respectively, and positioning is accordingly performed. FIG. 4Cillustrates a state where an inclined surface of the first protrusion235 is in contact with the exterior cover 241 and the first receivingportion 242, and the latch member 222 is slightly rotated in theclockwise direction in FIG. 4C around the rotary shaft 232. FIG. 4Dillustrates a state where the sheet post-processing apparatus 200 isfurther moved in the vertical downward direction, and the latch member222 is rotated in the clockwise direction. FIG. 4E illustrates a statewhere the sheet post-processing apparatus 200 is completely mounted onthe apparatus main body 100. The first protrusion 235 is biased towardthe first receiving portion 242 by an elastic force of the elasticmember 233. In other words, the first protrusion 235 of the latch member222 is engaged with the first receiving portion (engaged portion) 242 ofthe apparatus main body 100 by the elastic force of the elastic member233. As illustrated in FIG. 4B to FIG. 4E, the second protrusion 236 isnot in contact with the exterior cover 240 or the second receivingportion 243 when the sheet post-processing apparatus 200 is mounted.

In contrast, when the sheet post-processing apparatus 200 is demountedfrom the apparatus main body 100, the sheet post-processing apparatus200 is lifted up in the substantially vertical direction to cause thelatch member 222 to operate in order of FIG. 4E to FIG. 4A.

FIG. 5A illustrates a state of the sheet post-processing apparatus 200when an external force in an arrow direction is applied to the sheetpost-processing apparatus 200 from a side provided with the stackingunits 208 and 210 to 212. The sheet post-processing apparatus 200 isrotated around a lower right end portion (250) of the apparatusillustrated in FIG. 5A and is inclined while the sheet stacking portionside is raised. In other words, FIG. 5A illustrates a state of the latchmember 222 and the peripheral members thereof in a case where the sheetpost-processing apparatus 200 is inclined, with respect to the apparatusmain body 100, in a direction in which engagement of the firstprotrusion 235 with the first receiving portion 242 is released. Thesecond protrusion 236 gets under the second receiving portion (contactportion) 243 and comes into contact with the second receiving portion243 due to the inclination of the sheet post-processing apparatus 200.In other words, the second protrusion 236 is locked by the secondreceiving portion 243 when the sheet post-processing apparatus 200 isinclined with respect to the apparatus main body 100 in theabove-described direction. Accordingly, the inclination of the sheetpost-processing apparatus 200 with respect to the apparatus main body100 is regulated in such a manner that the sheet post-processingapparatus 200 is not inclined by an angle exceeding an angle illustratedin FIG. 5A (predetermined angle) even by the external force. In FIG. 5A,a position of a centroid 251 of the sheet post-processing apparatus 200is illustrated. Shapes of related components are determined in such amanner that the sheet post-processing apparatus 200 is not as inclinedas the centroid 251 is positioned beyond the rotation center 250 even ifthe sheet post-processing apparatus 200 is inclined.

The configuration of the first exemplary embodiment described aboveachieves the following effects. As illustrated in FIG. 1, the stackingunits 208 and 210 to 212 of the sheets are provided on a side oppositeto the direction in which the first protrusion 235 of the latch member222 protrudes with respect to the sheet post-processing apparatus mainbody (sheet stacking apparatus main body) 2000. Therefore, even in acase where a large number of sheets is stacked on any of the stackingunits 208 and 210 to 212, the sheet post-processing apparatus 200 ishardly inclined because the first protrusion 235 of the latch member 222is engaged with the first receiving portion 242.

Further, even if an external force is applied to the sheetpost-processing apparatus 200 from the side provided with the stackingunit 208, the sheet post-processing apparatus 200 is not rotated by thepredetermined angle or more by contact between the second protrusion 236of the latch member 222 and the second receiving portion 243, whichstabilizes the posture of the sheet post-processing apparatus 200. Evenin a case where the sheet post-processing apparatus 200 is inclined bythe predetermined angle, the sheet post-processing apparatus 200 is notas inclined as the centroid 251 of the sheet post-processing apparatus200, with no sheet being stacked on any of the stacking units 208 and210 to 212, is positioned beyond the rotation center 250. Accordingly,when the external force applied to the sheet post-processing apparatus200 is removed, the sheet post-processing apparatus 200 returns to theoriginal position by its own weight. The external force described hereis a force applied by a user. For example, the external force is appliedin a case where the user unintentionally puts a hand on the sheetpost-processing apparatus 200 to move the image forming apparatus. Inthe normal printing operation, such an external force is not applied tothe sheet post-processing apparatus 200, and the side provided with thestacking unit 208 is not raised. A plurality of latch units 230 isprovided on the apparatus in the width direction (vertical direction ona paper surface in FIG. 1 or FIG. 5A), and the latch units 230 aredisposed near the end portions of the apparatus in the width direction.This prevents the sheet post-processing apparatus 200 from being raisedfrom the apparatus main body 100 also when the external force is appliedto the sheet post-processing apparatus 200 from the width direction. Inother words, even in the configuration in which the fitting length ofthe positioning member of the sheet post-processing apparatus with theapparatus main body is not sufficiently long, the posture of the sheetpost-processing apparatus with respect to the main body is stabilized.The configuration in the first exemplary embodiment makes it possible tocontribute to downsizing and cost reduction of the apparatus.

It is possible to mount and demount the sheet post-processing apparatus200 on/from the apparatus main body 100 without causing a user toperform an operation such as release of the latch members. Further, thelength relationship is set in such a way that the positioning membersare fitted in the apparatus main body 100 before the connector and thelatch members are fitted in the apparatus main body 100. As a result,high workability can be achieved when the sheet post-processingapparatus 200 is mounted on the apparatus main body 100.

In the first exemplary embodiment, the sheet post-processing apparatusis described as the optional apparatus that is to be mounted on the topsurface of the apparatus main body 100 in the vertical direction.However, the optional apparatus is not limited thereto. For example,similar effects are achievable by other optional apparatuses such as areading scanner, and an auto document feeder (ADF).

A configuration described in a second exemplary embodiment is the sameas the configuration in the first exemplary embodiment except for alatch unit 300. Therefore, description of the configuration other thanthe latch unit 300 is omitted.

The latch unit 300 according to the second exemplary embodiment is to bedescribed with reference to FIGS. 6A to 6D.

The latch unit 300 includes a base plate 301, a rotary shaft 302, anelastic member (torsion coil spring) 303, and a latch member 304. Thebase plate 301 is fixed to the housing of the sheet post-processingapparatus 200. The rotary shaft 302 is fixed to the base plate 301, andthe latch member 304 is rotatable around the rotary shaft 302. In theelastic member 303, the rotary shaft 302 penetrates through a coilportion, one end of an arm is hooked on the base plate 301, and theother end is hooked on the latch member 304. The latch member 304 isbiased so as to be rotated in the clockwise direction in FIG. 6A. Thelatch member 304 is brought into contact with a mechanical stopper 305provided on the base plate 301, and a posture of the latch member 304 isaccordingly determined. The latch member 304 includes a first protrusion306, and the base plate 301 includes a second protrusion 307. The firstprotrusion 306 protrudes in a direction intersecting a direction inwhich the latch member 304 extends. The second protrusion 307 isprovided on a distal end side of the latch unit 300 relative to thefirst protrusion 306, and protrudes in a direction opposite to thedirection in which the first protrusion 306 protrudes.

FIG. 6A is a diagram illustrating a state where the latch member 304 ispositioned at a home position. FIG. 6A illustrates a state before thelatch member 304 and the latch member receiving portion 227 come intocontact with each other. Before the state illustrated in FIG. 6A, thepositioning members 220 and 221 are fitted in the positioning memberreceiving holes 225 and 226, respectively, and positioning isaccordingly performed. FIG. 6B illustrates a state where the sheetpost-processing apparatus 200 is slightly moved downward from theposition illustrated in FIG. 6A, the first protrusion 306 and theexterior cover 241 are in contact with each other, and the latch member304 is rotated in the counterclockwise direction in FIG. 6B around therotary shaft 302. FIG. 6C illustrates a state where the sheetpost-processing apparatus 200 is completely mounted on the apparatusmain body 100. The first protrusion 306 is biased toward the firstreceiving portion 242 by an elastic force of the elastic member 303. Inother words, the first protrusion 306 of the latch member 304 is engagedwith the first receiving portion (engaged portion) 242 of the apparatusmain body 100 by the elastic force of the elastic member 303. Asillustrated in FIG. 6A to FIG. 6C, the second protrusion 307 is not incontact with the exterior cover 240 or the second receiving portion 243when the sheet post-processing apparatus 200 is mounted.

In contrast, when the sheet post-processing apparatus 200 is demountedfrom the apparatus main body 100, the sheet post-processing apparatus200 is lifted up in the substantially vertical direction to cause thelatch member 304 to operate in order of FIG. 6C to FIG. 6A.

FIG. 6D illustrates the latch unit 300 and peripheral members thereof ina state where the sheet post-processing apparatus 200 is inclined withrespect to the apparatus main body 100 in a direction in whichengagement of the first protrusion 306 with the first receiving portion242 is released. The second protrusion 307 is in contact with the secondreceiving portion 243 due to inclination of the sheet post-processingapparatus 200.

In contrast, the latch member 304 is in contact with the exterior cover241 by the biasing force of the elastic member 303. Therefore, theinclination of the sheet post-processing apparatus 200 is regulated insuch a way that the sheet post-processing apparatus 200 is not asinclined as to exceed the posture (predetermined angle) illustrated inFIG. 6D by the external force. The configuration, in which the sheetpost-processing apparatus 200 is not as inclined as the centroid 251 ispositioned beyond the rotation center 250, is also similar to theconfiguration of the first exemplary embodiment.

According to the above-described configuration, the apparatus can beprovided in which the posture of the sheet post-processing apparatuswith respect to the main body is stabilized even if the fitting lengthof the positioning member of the sheet post-processing apparatus withthe apparatus main body is not long. The configuration of the secondexemplary embodiment is effective in a case where there is no space forinstallation of constituent components of the latch unit 300 inside thesheet post-processing apparatus 200 but there is a space forinstallation of the constituent components of the latch unit 300 insidethe apparatus main body 100.

The configuration described in a third exemplary embodiment is the sameas the configuration of the first exemplary embodiment except for alatch unit 400. Therefore, description of the configuration other thanthe latch unit 400 is omitted.

A diagram on the left side in FIG. 7 is a front view of the latch unit400, and a diagram on the right side is a right side view of the latchunit 400.

The latch unit 400 includes a base plate 401, a rotary shaft 402, anelastic member (torsion coil spring) 403, and a latch member 404. Thebase plate 401 includes a mechanical stopper 405. The base plate 401 isfixed to the housing of the sheet post-processing apparatus 200. Thelatch member 404 includes a first protrusion 406. The first protrusion406 protrudes in a direction intersecting a direction in which the latchmember 404 extends.

Unlike the first exemplary embodiment, the latch member 404 includes asecond protrusion 407 at a distal end of the latch member 404. Thesecond protrusion 407 extends in an axial direction of the rotary shaft402. Although details are described below, the apparatus main body 100includes a second receiving member 408 and a second receiving portion409. As illustrated in the right side view, the second protrusion 407extends so as to get across the second receiving portion 409.

FIGS. 8A to 8C illustrate an operation of inserting the latch unit 400according to the third exemplary embodiment into the apparatus main body100, in order.

FIG. 8A illustrates a state of the latch unit 400 and peripheral membersthereof before the latch member 404 and the latch member receivingportion 227 come into contact with each other. Before the stateillustrated in FIG. 8A, the positioning members 220 and 221 illustratedin FIG. 2A are fitted in the positioning member receiving holes 225 and226, respectively, and positioning is accordingly performed. FIG. 8Billustrates a state where the sheet post-processing apparatus 200 isslightly moved in the vertical downward direction from the positionillustrated in FIG. 8A, the first protrusion 406 and the exterior cover241 are in contact with each other, and the latch member 404 is rotatedin the clockwise direction in FIG. 8B around the rotary shaft 402. FIG.8C illustrates a state of the latch unit 400 and peripheral membersthereof when the sheet post-processing apparatus 200 is completelymounted on the apparatus main body 100. The first protrusion 406 isbiased toward the first receiving portion 242 by an elastic force of theelastic member 403. As illustrated in FIG. 8A to FIG. 8C, the secondprotrusion 407 is not in contact with the exterior cover 240 or thesecond receiving member 408 when the sheet post-processing apparatus 200is mounted.

In contrast, when the sheet post-processing apparatus 200 is demountedfrom the apparatus main body 100, the sheet post-processing apparatus200 is lifted up in the substantially vertical direction to cause thelatch member 404 to operate in order of FIG. 8C to FIG. 8A.

FIG. 8D illustrates the latch unit 400 and peripheral members thereofwhen the apparatus main body 100 and the sheet post-processing apparatus200 are in the state illustrated in FIG. 5A. The second protrusion 407is in contact with the second receiving portion 409 due to inclinationof the sheet post-processing apparatus 200. On the other hand, the latchmember 404 is in contact with the exterior cover 241. Accordingly,inclination of the sheet post-processing apparatus 200 is regulated insuch a way that the sheet post-processing apparatus 200 is not asinclined as to exceed the posture (predetermined angle) illustrated inFIG. 8D by the external force. The configuration, in which the sheetpost-processing apparatus is not as inclined as the centroid 251 ispositioned beyond the rotation center 250 when the sheet post-processingapparatus 200 is inclined, is similar to the configuration of the firstexemplary embodiment.

According to the above-described configuration, the apparatus can beprovided in which the posture of the sheet post-processing apparatuswith respect to the main body is stabilized even if the fitting lengthof the positioning member of the sheet post-processing apparatus withthe apparatus main body is not long.

While the present invention has been described with reference to theexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2016-256754, filed Dec. 28, 2016, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A mount apparatus to be mounted in a verticaldirection on a top surface of a main body of an image forming apparatusconfigured to form an image on a sheet, the mount apparatus comprising:a latch member extending toward the main body from a surface facing thetop surface of the main body, wherein the latch member is rotatablearound a rotational axis extending in a direction orthogonal to thevertical direction and includes a first protrusion and a secondprotrusion, wherein the first protrusion protrudes in a directionintersecting the direction in which the latch member extends, the secondprotrusion is provided on a distal end side of the latch member relativeto the first protrusion and protrudes in a direction opposite to thedirection in which the first protrusion protrudes; and a biasing memberconfigured to bias the latch member in a predetermined rotationdirection, wherein, in a state where the mount apparatus is mounted onthe main body, the first protrusion is inserted into the main bodythrough an opening provided on the top surface of the main body and isengaged with an engaged portion of the main body by a biasing force ofthe biasing member, and wherein, in a case where the mount apparatus isinclined with respect to the main body in a direction in whichengagement of the first protrusion with the engaged portion of the mainbody is released, the second protrusion is engaged with the main body soas to regulate the inclination of the mount apparatus.
 2. The mountapparatus according to claim 1, further comprising: a conveyance unitconfigured to receive a sheet from the main body and to convey thesheet; a discharging unit configured to discharge the sheet conveyed bythe conveyance unit to outside of the mount apparatus; and a tray onwhich the sheet discharged from the discharging unit is stacked, whereinthe tray extends, with respect to the mount apparatus, in a directionopposite to the direction in which the first protrusion of the latchmember protrudes.
 3. The mount apparatus according to claim 2, whereinthe tray is part of a plurality of trays, each provided at a positionarranged in the vertical direction.
 4. An image forming apparatus,comprising: a main body of an image forming apparatus configured to forman image on a sheet; and a mount apparatus mounted on a top surface ofthe main body in a vertical direction, wherein the mount apparatusincludes: a latch member extending toward the main body from a surfacefacing the top surface of the main body, wherein the latch member isrotatable around a rotational axis extending in a direction orthogonalto the vertical direction and includes a first protrusion and a secondprotrusion, wherein the first protrusion protrudes in a directionintersecting the direction in which the latch member extends, the secondprotrusion is provided on a distal end side of the latch member relativeto the first protrusion and protrudes in a direction opposite to thedirection in which the first protrusion protrudes, and a biasing memberconfigured to bias the latch member in a predetermined rotationdirection, wherein, in a state where the mount apparatus is mounted onthe main body, the first protrusion is inserted into the main bodythrough an opening provided on the top surface of the main body and isengaged with an engaged portion of the main body by a biasing force ofthe biasing member, and wherein in a direction in which engagement ofthe first protrusion with the engaged portion of the main body isreleased, the second protrusion is engaged with the main body so as toregulate inclination of the mount apparatus.
 5. The image formingapparatus according to claim 4, wherein the mount apparatus includes: aconveyance unit configured to receive a sheet from the main body and toconvey the sheet, a discharging unit configured to discharge the sheetconveyed by the conveyance unit to outside of the mount apparatus, and atray on which the sheet discharged from the discharging unit is stacked,wherein the tray extends in a direction opposite to the direction inwhich the first protrusion of the latch member protrudes.
 6. The imageforming apparatus according to claim 5, wherein the tray is part of aplurality of trays, each provided at a position arranged in the verticaldirection.
 7. A mount apparatus to be mounted in a vertical direction ona top surface of a main body of an image forming apparatus configured toform an image on a sheet, the mount apparatus comprising: a latch memberextending toward the main body from a surface facing the top surface ofthe main body, wherein the latch member is rotatable around a rotationalaxis extending in a direction orthogonal to the vertical direction; anda biasing member configured to bias the latch member in a predeterminedrotation direction, wherein, in a state where the mount apparatus ismounted on the main body, the latch member is inserted into the mainbody through an opening provided on the top surface of the main body andis engaged with the main body by a biasing force of the biasing member.8. The mount apparatus according to claim 7, further comprising: aconveyance unit configured to receive a sheet from the main body and toconvey the sheet; a discharging unit configured to discharge the sheetconveyed by the conveyance unit to outside of the mount apparatus; and atray on which the sheet discharged from the discharging unit is stacked,wherein the tray extends, with respect to the mount apparatus, in adirection opposite to the direction in which the latch member protrudes.9. The mount apparatus according to claim 8, wherein the tray is part ofa plurality of the trays, each provided at a position arranged in thevertical direction.